Pavilanis Layout:Layout 1 1/9/09 8:25 AM Page 38 A worker uses the caliper weld inspection method to measure fillet welds in a tubular assembly. How to Accurately Measure Fillet Welds A tubular assemblies manufacturer devised a unique method for taking fillet weld readings BY JOE PAVILANIS Woolf Aircraft Products, Inc., got its start in Wayne, Mich., in 1942 fabricating tubular assemblies for B-24 bombers. Today, the company operates out of a 100,000-sq-ft facility in Romulus, Mich., and supplies tubular assemblies for a wide variety of industries, including defense, transportation, power generation, and agriculture. Aircraft and aerospace remain prime segments of the company’s business, however. Its 125 employees can fabricate just about any type of tubular assembly. Woolf Aircraft has the capability of bending tubing from 0.125 through 7 in. in diameter and has a selection of more than 450 radius dies, which gives its customers many options. It also has an extensive material inventory, stocking more than 1400 different sizes and types of material. The company commonly fabricates stainless steel, Inconel™, carbon steel, chrome-moly steel, aluminum, and titanium, and also has experience with magnesium, Hastelloy® X, AL6XN, and other exotic alloys. One of the company’s recent achievements was to become registered to SAE AS9100B, Quality Management Systems — Aerospace — Requirements, in 2008. It has 13 welders qualified to the requirements of AWS D17.1, Specificiation for Fusion Welding for Aerospace Applications, in all metals that are fabricated in thickness ranges from 0.020 to 0.250 in. thick, as well as various projectspecific certifications to the ASME Boiler & Pressure Vessel Code, Section IX, and an array of customer-specific welding specifications. JOE PAVILANIS ([email protected]) is process/quality engineer, Woolf Aircraft Products, Inc., Romulus, Mich. 38 FEBRUARY 2009 Pavilanis Layout:Layout 1 1/9/09 8:25 AM Page 39 Fig. 1 — The adapter mounts to a digital caliper designed to seat directly onto the corner of a 90-deg angle. A Fig. 2 — The reading gives the distance from the weld root to the weld face, which is the weld throat. B Fig. 3 — A — When touching the weld face, the digital scale shows the actual distance from the root to the face, providing a measurement of the actual weld throat; B — a close-up of the throat measurement. Problem/Issue Many of the weld sizes that Woolf is required to produce are often less than 0.125 in. and as small as 0.040 in. The company has found that traditional fillet weld gauges do not work that well for inspecting and verifying the sizes of welds. Even if you have a custom gauge made as Woolf has done, it is often so small it is difficult to make any sort of determination. This makes the inspection of these welds very slow and difficult. In addition, it is difficult to obtain actual readings when doing dimensional inspection reports. Currently, most gauges that are used to measure welds are attribute by nature, which means that they only make a comparison to a template rather than an actual reading. There are some gauges that will provide a measurement against an imprinted scale to allow an estimation of the size, but these gauges are not calibrated and do not offer a variable reading that is traceable to the National Institute of Standards and Technology (NIST). As a com- pany that is registered to the quality management systems of ISO9001:2000 and AS9100B, Woolf must meet the requirement that all measurement systems used to accept product be traceable to NIST. Woolf Aircraft needed a tool that could provide an actual “variable” reading over a range of fillet weld sizes and be traceable to NIST. Officials there believed that most industries have that same need; therefore, the company developed an inspection tool/system that it can use to measure a leg length, as well as the actual weld throat. With these two known measurements, this information can then be used to determine the actual size as well as the convexity/concavity of a specific fillet weld. Caliper Weld Inspection Method Workers at Woolf Aircraft made an adapter that mounts to a digital caliper that has been designed to seat directly into the corner of a 90-deg angle — Fig. 1. The digital scale is then set to “zero” and then used in the same manner against the fillet weld. The reading on the caliper gives the distance from the “root” (corner) of the weld to the face of the weld, which is the weld throat — Fig. 2. When touching the face of the weld, the digital scale will reveal the actual distance from the root of the weld to the face, which is the actual weld throat — Fig. 3. Using a similar technique to measure the length of a leg, as shown in Fig. 4, the individual leg lengths will be determined. A traditional caliper is used in this measurement. Now that the two variables are known — leg length and actual throat length — many determinations can be made regarding the weld size. Since the example shown in Fig. 4 is a 45-deg right triangle, then both legs should be equal length — Fig. 5. Applicable Industries Officials at Woolf Aircraft believe this measurement system can be useful to a WELDING JOURNAL 39 Pavilanis Layout:Layout 1 1/12/09 1:53 PM Page 40 B A Fig. 4 — A — A similar technique, using a traditional caliper, is used to measure the leg length; B — a close-up of the leg measurement. wide variety of industries besides aerospace, such as military, automotive, commercial, power generation, etc., and that the entire welding community and every industry it serves is in need of the ability to make variable measurements. This article provides a basic overview of how the system works. You may have questions as to how useful it is if your fillet weld is not a 90-deg angle, or if it can be used to check for misalignment or to measure weld reenforcement on tube and pipe groove joints. Options are available to handle those situations that are not covered in this discussion. Contact the author for additional information. Conclusions This system allows for variable measurement of the weld legs, actual throat length, calculation of the theoretical throat length, convexity, and concavity. Also, by using calibrated digital instruments during the inspection, the inspection system is then traceable to the National Institute of Standards and Technology, which satisfies the expectations of Fig. 5 — Once the two variables are known, other factors are known about the weld size. quality management systems such as ISO 9001:2000 and SAE AS9100B. These stan- DO YOUR OWN TESTING Bend Testers - Bend Specimen Cutting Fixtures - Coupons -Tensile Testers Acknowledgments BT1B Visit our website for all sizes and models available www.fischerengr.com ! (937)754-1750 BT1C TT1 BSC-1PLT For info go to www.aws.org/ad-index 40 JUNE, 03 WELDING JOURNAL FEBRUARY 2009 dards require that anything used to accept product dimensions must be calibrated. Using this system helps Woolf Aircraft meet the measurement expectations of the various quality system requirements and provide variable measurements without the need for cutting and etching in order to obtain these measurements.◆ The author would like to thank the following individuals at Woolf Aircraft for their support in this project and with the preparation of this article: Adam Woolf; Al Swistara, vice president, Engineering; Doug Kochan, toolmaker; Dane Borowski, tube fabricator; and Adam Pavilanis, weld engineer intern.